This invention relates to devices for the electrolytic treatment of liquids, and more particularly to an electrolytic treatment apparatus that is arranged to provide for very rapid changes of electrode assemblies that are provided as complete, self-contained reactor cartridges, whereby to virtually eliminate maintenance down time of the treatment apparatus for electrode replacement, cleaning and other operational requirements.
Numerous electrolytic devices have been developed over the years for the treatment of liquids. Many of these treatment devices make use of a plurality of electrodes that are placed within a housing and connected to a DC power source. As the liquid is passed between the electrodes, contaminants precipitate and become separable. A wide variety of electrode geometries and configurations have been developed, with the idea that one geometry or configuration may treat or function better with different liquids and contaminants than others, or would require less power to operate.
Providing and managing clean water is the greatest problem faced by municipalities, industry and nations. For decades, the industry has relied primarily on chemicals to treat a number of aqueous solutions, including water for drinking, raw sewage, and industrial process fluids. However, increasingly high levels of pollution and the rapid decline of clean water sources is requiring industries of all types to seek better, more cost effective ways to improve treatment and remove a much higher percentage of contaminants. Chemicals are not only expensive, but they significantly reduce the amount of water that can be reclaimed and increase the amount of sludge that must be disposed. Chemicals also limit the percentage of contaminants than can be removed, making it difficult to meet present and future treatment requirements and near impossible to provide water suitable for reuse. Chemicals used for killing microorganisms within drinking water have also been shown as a health risk and is becoming less acceptable. Although several other methods have been developed and are presently being used for treating liquids, such as distillation, reverse osmosis, and ion exchange, these technologies either cost too much to operate, will not treat larger volumes of liquid, will not treat liquids containing high concentrations of suspended solids, or significantly reduce the amount of clean liquid that can be reclaimed.
Recent efforts to find better, more cost effective solutions for improving treatment requirements have raised considerable interest in other technologies that do not involve the use of chemicals. Industries and governments have begun looking into electrolytic treatment, which has been a long ignored but proven method for electrochemically precipitating and removing impurities from liquid. This type of electrolytic treatment typically involves a reaction housing that contains two or more electrodes spaced closely to each other and connected to a source of power, preferably Direct Current (DC). The liquid becomes treated as it is introduced between the electrodes and is subjected to an electrical field, causing impurities to precipitate to form a flocculent that is separable from the liquid using a number of mechanical and non mechanical methods, including filters, plate clarifiers, sedimentation, centrifugal separators, and floatation devices with skimmers.
In addition, the electrical field causes microorganisms to be killed, and other impurities of cellular nature to rupture, releasing liquid contained within them and further reducing the amount of produced sludge that must be handled or disposed. Also during the treatment process, hydrogen and oxygen gasses become present, furthering treatment by oxidizing the impurities. Electrolytic treatment offers a significant advantage over chemicals and many other methods of treating liquid, as it provides a much wider spectrum of treatment by precipitating and oxidizing impurities, destroying organisms, and dewatering sludge, all within a single pass between two or more electrodes that are connected to a source of power.
Numerous electrolytic devices have been developed through the years for the treatment of liquids using a number of different electrodes and configurations in an effort to provide improved performance. Among these improvements include distributing liquid more evenly between the electrodes, reducing electrical power consumption, preventing gasses and solids from being trapped in the housing, reducing the size and cost, reducing electrode wear and replacement time, or providing a method for treating larger liquid volumes.
Despite the many intended improvements, electrolytic devices have remained practically unheard of and rarely used in the industry. The reason for this is previous devices do not provide a quick and practical method for inserting and removing electrodes within the reaction housing for maintenance. Practical methods for providing maintenance is essential, as electrodes will often become coated with contaminants and/or dissolve in the water, requiring them to be removed from the housing either for cleaning or replacement. Different methods have been employed in the past to help solve many problems related to electrodes dissolving and collecting scalings or coatings, including reversing the polarity of the electrodes or shorting them to ground. These techniques will help extend the operational life expectancy of the electrodes; however, this can never fully replace having to perform maintenance on them.
Some commercial applications will cause the electrodes to coat within less than one hour, even with the use of polarity reversing. Methods for automatically cleaning electrodes while they remain in the housing also have been implemented into some devices using a combination of pumps, valving, and storage tanks for holding acidic cleaning solutions. This method has proven to work well; however, it requires additional space and is too expensive to incorporate into smaller devices. Despite the various attempts to reduce maintenance, a certain degree of manual maintenance is unavoidable and a practical method for providing maintenance is essential.
The problem with devices of the prior art is they employ cumbersome designs that make maintenance difficult, time consuming, and often labor-intensive. Several steps must be taken with previous devices in order to remove any coverings, support structures, and/or electrical connections before electrodes can be removed from the reaction housing for maintenance. The same amount of time taken to remove electrodes from previous devices is required to reinstall them back in the housing, which soon adds up to costly labor expenses, not to mention the necessary downtime while maintenance was being performed. In addition, previous devices consist of a specific reaction housing designed to function with a particular geometry of electrode. This prevents them from using other types of electrodes within the same housing that may be more readily available, cost less, or might work better with certain liquids. Additionally, these devices require the operator to source their own electrode material and fabricate them for replacement, instead of being able to simply purchase a cartridge containing the electrodes that could be installed in one easy step into the housing.
The frequency of electrode replacement due to dissolving in the liquid will depend on the size and quantity of the electrodes, duration of operation, and composition of the liquid being treated. Electrode replacement could be required within hours to weeks depending on the application. Some liquids contain contaminants that can coat the electrodes within minutes, preventing proper DC current transfer between them and requiring the electrodes to be frequently removed and cleaned. Although acid can be introduced directly into the housing of some devices to clean the electrodes, certain applications may not permit this, especially if the device is being used to treat drinking water.
Aside from electrodes dissolving or being coated with contaminants, the composition of liquids to be treated may change, requiring electrodes to be removed from the device and be replaced with different ones, such as electrodes made from stainless steel or electrodes made from aluminum as different metals may achieve better treatment results. These factors place prior art devices at a critical disadvantage, as they typically employ cumbersome construction that make electrode replacement difficult, time-consuming, and often labor-intensive.
Devices of the prior art all require several steps to be taken before the electrodes can be placed in or removed from the housing. As an example, U.S. Pat. No. 820,113 uses a plurality of cylindrical electrodes placed vertically within a closed housing. However, the fasteners, electrodes, cover, and electrical connections are all individual components, requiring each of them to be removed separately from the housing. The same amount of time taken to remove the electrodes is required to reassemble them back in the housing, resulting in costly labor expenses, as well as all the down time while maintenance was being performed.
U.S. Pat. No. 6,139,710, uses a plurality of vertical electrode plates within a treatment housing. The electrodes are placed within the housing separate from electrical connections and the cover, requiring additional steps be performed for the electrodes to be replaced. This device makes use of a plurality of non-conductive rods for spacing the electrodes and interconnecting them so they may be removed together from the housing. While this allows removal of the electrodes as a unit, the cover and all electrical connections must first be disassembled individually. Further, the installation process requires each electrode to be placed within the housing one at a time, requiring an extensive amount of time and labor, along with a degree of difficulty as the number and size of the electrodes are increased to treat larger volumes of liquid. Then wiring is required, followed by installation of the cover. The obvious shortcoming of electrolytic treatment devices that make use of a plurality of electrodes is that they do not allow all of the electrodes, cover, and electrical wiring to be removed from and installed into the housing as a single, replaceable component.
In its basic concept this invention provides an electrolytic treatment apparatus in which a plurality of electrodes, any wiring connections thereto, electrode supports, and any liquid dispersion structures are integrated together into a self-contained, self-supporting reactor cartridge unit arranged for rapid installation into and removal from a corresponding reaction vessel as self-contained, exchangeable and interchangeable units.
It is by virtue of the foregoing basic concept that the principal objective of this invention is achieved; namely, the provision of an electrolytic treatment apparatus that overcomes the limitations and disadvantages of electrolytic treatment devices of the prior art.
Another object of this invention is the provision of an electrolytic treatment apparatus of the class described which, by providing exchangeable reactor cartridges, substantially eliminates downtime of electrolytic treatment systems due to electrode wear, failure and need for cleaning.
Another object of this invention is the provision of an electrolytic treatment apparatus of the class described which completely eliminates the heretofore necessary custom, in-house fabrication of electrodes and electrode support and wiring connections required in prior art electrolytic treatment systems.
Still another object of this invention is the provision of an electrolytic treatment apparatus of the class described in which different reactor cartridges may be provided with electrodes of different material and/or configuration whereby reactor cartridges may be selected and exchanged as desired or needed in order to treat different liquids and/or contaminants as may be needed.
A further object of this invention is the provision of an electrolytic treatment apparatus of the class described which is of simplified construction for economical manufacture.
The foregoing and other objects and advantages of the present invention will appear from the following detailed description, taken in connection with the accompanying drawings of preferred embodiments.